[Ifeffit] Measurment of size of nanoparticles using one measurement of sample

[pushkar shejwalkar]

Dear All,
   I am currently trying to find out the size of my Pd nanoparticles using
EXAFS analysis. But I am totally new to this field and I have no physics
background as well. With this I started digging into the email archives as
to if it is possible to speculate the size of the nanoparticles that I
have. My preliminary information from SEM lets me start from the point
where the nanoparticles are around 2-3 nm in size and about spherical in
nature. I started with the following thread from archive

http://millenia.cars.aps.anl.gov/pipermail/ifeffit/2013-October/011474.html

and it was pretty useful as well. I read the documents and other threads
involved in it. and then I realized that with the knowledge of amplitude of
known (lets say in this case Pd foil) and my sample I can find out the
extent to which the Pd atoms are present at the farthest distance. by doing
so I can find out what the nanoparticles size. To be specific I am talking
about this particular paper.

http://scitation.aip.org/docserver/fulltext/aip/journal/jap/94/1/1.1581344.pdf?expires=1450258091&id=id&accname=2094377&checksum=FA0334640D699848A702CC80087BFF0F

(http://dx.doi.org/10.1063/1.1581344)

I am using this paper since it works with spherical nanoparticles and hence
my assumptions can best be supported by this model. I am open to other
references as well and I would cite them all if they are useful.
Now my question is, in order to make up to the reduced amplitude, it is
recommended that for spherical nanoparticles only two variables in fitting
parameteres are needed 1) Radius 2) amplitude reduction factor (SO2)
I think I have understood the basic concept as to why the amplitude is
reduced and somehow we need to increase the number N of number of
paths/number of atoms in the cluster so that the amplittude will now
increase so much so that it would match the theory.
BUT what I have not understood is how to do so? e,g do we do that during
fitting? in artemis? in which case the amplitude is by default adjusted to
get the fit and now there is no difference in the absolute value of x(R)
(A-3Ao) Y-axis.
OR have I misunderstood something? Could someone shine a light on this
please.
Best
Pushkar
-- 
Best Regards,
Pushkar Shejwalkar.
Post-doctoral -Researcher,
Tokyo Engineering University,
Tokyo-to
Japan
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